Generally, a circuit carrier (e.g. a printed circuit board) and a transformer are included in an electronic device such as a LCD television. The transformer is mounted on the circuit carrier to form a circuit carrier and transformer assembly. The transformer has become an essential electronic component for voltage regulation into required voltages for the electronic device.
FIG. 1 is a schematic exploded view illustrating a transformer and a circuit carrier according to prior art. As shown in FIG. 1, the transformer 1 is mounted on the circuit carrier 11. As shown in FIG. 1, the transformer 10 principally comprises a magnetic core assembly 12, a bobbin 13, a primary winding coil 14 and a secondary winding coil 15. The primary winding coil 14 and the secondary winding coil 15 are wound around a first winding part 131 and a second winding part 132 of the bobbin 13, respectively. In addition, a first side plate 131a and a second side plate 131b are arranged on opposite sides of the first winding part 131 of the bobbin 13. A third side plate 132a and a fourth side plate 132b are arranged on opposite sides of the second winding part 132 of the bobbin 13. The second side plate 131b of the first winding part 131 is separated from the third side plate 132a of the second winding part 132 by a gap d. Due to the gap d, a desired creepage distance is maintained between the primary winding coil 14 and the secondary winding coil 15. Moreover, two bobbin bases 16 are externally and vertically extended from the first side plate 131a of the first winding part 131 and the fourth side plate 132b of the second winding part 132, respectively. A plurality of pins 17 are disposed on the bobbin bases 16 and inserted into corresponding perforations (not shown) of the circuit carrier 11, so that the transformer 10 is fixed on the circuit carrier 11.
FIG. 2 is a schematic cross-sectional view illustrating a circuit carrier and transformer assembly shown in FIG. 1. Please refer to FIGS. 1 and 2. The circuit carrier and transformer assembly, however, still has some drawbacks. For example, after the pins 17 of the transformer 10 are inserted into corresponding perforations of the circuit carrier 11, the bobbin bases 16 of the transformer 10 are sustained against the surface of the circuit carrier 11. Since the bobbin bases 16 have inherent volume, the bobbin bases 16 occupy extra space above the circuit carrier 11. In other word, the circuit carrier and transformer assembly is detrimental to minimization and slimness of the electronic device. Moreover, since the gap d between the second side plate 131b of the first winding part 131 and the third side plate 132a of the second winding part 132 maintains the desired creepage distance between the primary winding coil 14 and the secondary winding coil 15, the second side plate 131b and the third side plate 132a are very close to the circuit carrier 11 after the transformer 10 is mounted on the circuit carrier 11. If the distance between the second side plate 131b (or the third side plate 132a) and the circuit carrier 11 is smaller than 1 mm, the creepage distance between the primary winding coil 14 and the secondary winding coil 15 is shortened and thus the electrical safety is reduced.
There is a need of providing a circuit carrier and transformer assembly to obviate the drawbacks encountered from the prior art.